Today, the number of applications utilizing GNSS information is rapidly increasing. For example, GNSS information is a valuable tool for geodesists. Geodesists commonly use GNSS devices to determine the location of a point of interest anywhere on, or in the vicinity of, the Earth. Often, these points of interest are located at remote destinations which are difficult to access. Thus, compact, easy-to-carry positioning devices are desired.
GNSS receivers work by receiving data from GNSS satellites. To achieve millimeter and centimeter level accuracy, at least two GNSS receivers are needed. One receiver is positioned at a site where the position is known. A second receiver is positioned at a site whose position needs to be determined. The measurement from the first receiver is used to correct GNSS system errors at the second receiver. In post-processed mode, the data from both receivers can be stored and then transferred to a computer for processing. Alternatively, the corrections from the first receiver, the known receiver, may be transmitted in real time (via radio modems, Global System for Mobile Communications (GSM), etc.) to the unknown receiver, and the accurate position of the unknown receiver determined in real time.
A GNSS receiver typically includes a GNSS antenna, a signal processing section, a display and control section, a data communications section (for real-time processing), a battery, and a charger. Some degree of integration of these sections is usually desired for a handheld portable unit.
Another challenge of portable GNSS units is precisely positioning a GNSS antenna on the point of interest for location measurement. Previously, bulky equipment such as a separate tripod or other external hardware was used to “level” the antenna. In other systems, light low-precision antennas were used. Such devices are bulky and difficult to carry. Thus, even as portable GNSS positioning devices become more compact, they suffer from the drawback of requiring additional bulky positioning equipment.
Thus, for high-precision applications, the use of multiple units to house the various components required for prior GNSS systems, and the requirement for cables and connectors to couple the units, creates problems regarding portability, reliability, and durability. In addition, the systems are expensive to manufacture and assemble.
Therefore, a high precision, portable, complete handheld GNSS device that overcomes these disadvantages of conventional devices is desired.